The aim of applying coatings is to improve surface properties of an object. Coatings can affect physical properties of various materials depending upon the composition of the coating materials, and the method of forming the coatings. Such properties include, but are not limited to, corrosion, adhesion, hardness, elasticity, temperature sensitivity and pressure sensitivity. Advances in coating technology have increased the quality, specificity (such as hydrophobicity) and compatibility of coatings with various objects and their use in various applications.
In response to increasing demand for damage tolerant, harsh-environment resistant coatings, a variety of relatively high-temperature alloy-coating processes have been developed and include for example plasma spray coating processes, thermal spray coating processes, and laser cladding processes. The disadvantages of these processes include the deleterious effects of high-temperature oxidation, evaporation, melting, crystallization, generation of residual stresses, gas release, high cost, and/or waste of raw materials, among others. These disadvantages may be minimized or eliminated in a recently developed coating process known as cold spray coating. Cold spray coating, sometimes referred to as cold gas-dynamic spraying, involves directing a stream of small solid metal particles projected from a spray device and traveling at high velocity onto a substrate. The cold spray process may be used to generate a high quality alloy coating, which has a low metal oxide content, a nearly theoretical bulk density, unusually high thermal and electrical conductivity, and low residual stresses. The cold spray process is economical, fast and useful in diverse applications.
In applications such as offshore oil drilling, floating drilling rigs, also referred to as platforms, often include direct-acting riser tensioners to compensate for wave-induced motion of the platform. Such direct-acting tensioners typically comprise a massive hydraulic cylinder that continuously dampens wave-induced platform motion, thereby stabilizing operations on the drilling rig. Typically, the hydraulic cylinders of the riser tensioners are mounted below the deck of the drilling rig in close proximity to the water, i.e., in a splash zone, and are therefore often exposed to an extremely corrosive and wear-inducing environment from airborne salt spray, seawater, ice, moving cables, and/or other debris. Additionally, the hydraulic cylinders may undergo thousands of wear-inducing displacements against multiple hydraulic cylinder seals. Therefore, there is a need for riser tensioner components comprising coatings having excellent wear and corrosion resistance and methods for making such components.